Effect of strand number on the folding and consequent self-assembly of β-sheet peptides into hydrogels with tuned properties

ORGN 457

Ronak Rughani, ronakcvr@udel.edu1, Darrin J. Pochan, pochan@udel.edu2, and Joel P. Schneider, schneijp@udel.edu1. (1) Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, (2) Department of Materials Science and Engineering, University of Delaware, 201 DuPont Hall, Newark, DE 19716
We have designed a family of 29 amino acid, three-stranded amphiphilic antiparallel β-sheets that undergo folding and self-assembly to form stimuli responsive hydrogels. Peptides adopt a random coil conformation at low pH, temperature or ionic strength, yet fold and self-assemble into β-sheet rich structures at higher pH, temperature or ionic strength resulting in the formation a viscoelastic hydrogel. Hydrogel bulk material properties, such as mechanical rigidity can be tuned by varying the turn sequence residues of the three-stranded sheet. In addition, the kinetics of self-assembly also influences the material rigidity. CD and IR spectroscopy reveals that these three-stranded peptides fold and self-assemble at lower temperatures and exhibit faster kinetics of self-assembly at pH 9.0 relative to MAX 1, a two-stranded hairpin of similar sequence. This indicates that the additional β-strand positively affects peptide folding and self-assembly and hydrogel properties. Rheological characterization demonstrates that the three-stranded peptides form more rigid hydrogels.
 

Bioorganic, Metal-Mediated Reactions, and Molecular Recognition
8:00 PM-10:00 PM, Tuesday, 30 August 2005 Washington DC Convention Center -- Hall A, Poster

Division of Organic Chemistry

The 230th ACS National Meeting, in Washington, DC, Aug 28-Sept 1, 2005